Anti-skid element



Sept. 2, 1969 SCHEUBA ET AL ANTI-SKID ELEMENT 2 Sheets-Sheet 1 FiledAug. 8, 1967 Ina/enters:

G b G. g Schleekar firfameys aye &

Norber c 8 Ge BY United States Patent 3,464,476 ANTI-SKID ELEMENTNorbert Scheuba, Essen, and Georg Schlecker, Rubgarten,

Germany, assignors to Beteiligungs-und Patentverwaltungsgesellschaft mitbeschrankter Haftung, Essen, Germany Filed Aug. 8, 1967, Ser. No.659,069 Claims priority, application Germany, Sept. 21, 1966, B 89,004Int. Cl. B60c 11/14, 27/20 US. Cl. 152-210 9 Claims ABSTRACT OF THEDISCLOSURE An anti-skid element for tires, in the form of a pin made ofwear-resistant material, a sleeve within which the pin is arranged andfrom one end of which the pin projects, and a sheath surrounding thesleeve. The sleeve is made of a material which is a good heat conductorwhile the sheath is made of an elastic material which is a poor heatconductor.

BACKGROUND OF THE INVENTION There exist various types of anti-skidelements, or socalled spikes, that are used to improve the tractionafforded by motor vehicle tires, these spikes being embedded in thetire. One such spike consists of a pin made of a wearresistant materialwhich is arranged, generally by way of a press-fit, in a sleeve, thelatter in turn being arranged Within a sheath. The pin projects out ofthe sleeve, and the sleeve and sheath have an enlarged head at the endopposite to that at which the pin projects out of the sleeve.

In heretofore conventional anti-skid elements of the above type, thesheath is made of a ceramic material having negligible elasticity, whilethe sleeve is made of a light metal and the pin, which occupies theblind bore of the sleeve, is made of a wear-resistant material. Thisarrangement reduces the amount which the rubber surrounding the spike isheated up, as compared to spikes where there are no sheathing means atall and where the light metal, which itself is a good heat conductor, isin direct contact with the rubber. On the other hand, such spikes havethe drawback that the outermost layer of the spike, i.e., the layerwhich is in direct contact with the rubber, is made of a material havingnegligible elasticity. This means that foreign particles, such as dust,dirt, sand, grit, salt, and the like, will inevitably work their waybetween the spike and the rubber, and this will ultimately grind awaythe rubber so that the bore within which the spike is seated will becomeenlarged, with the result that the spike will be loosened to the pointwhere it can fall out of the tire, especially under the influence of thecentrifugal force to which the spike is subjected as the wheel rotates.The same thing happens when the outermost layer of the spike is made ofa material which, though possessing some elasticity, is a good conductorof heat, because the heat generated by the spike will be transmitteddirectly to the tire, thereby deteriorating the rubber and causing partsof it to break away.

SUMMARY OF THE INVENTION It is, therefore, the primary object of thepresent invention to provide a spike or anti-skid element whichovercomes the above-described drawbacks of the heretofore known spikes,namely, to provide a spike which will not allow the rubber within whichthe spike is embedded to be heated up unduly to the point where therubber would deteriorate, and which resists the entry of foreignparticles between the spike and the rubber.

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With the above object in view, the present invention resides, basically,in an anti-skid element for tires, which element comprises a pin made ofWear-resistant material, a sleeve made of a material which is a goodconductor of heat, which pin is arranged in the sleeve and projects fromone end thereof, the other end of the sleeve having an enlarged head,and a sheath which surrounds the sleeve, including its head. Accordingto the present invention, the sleeve is made of an elastic materialwhich is a poor conductor of heat. I

In practice, the sheath will be made of a polymer, generally one havinga heat conductivity of between approximately 0.1 and 0.4 kcaL/m. h. C.,while the sleeve will be made of a material having a heat conductivityof between approximately and 400 kcal./m. h. C. The ratio of the heatconductivity of the polymer to the heat conductivity of the material ofwhich the sleeve is made will generally be between 1 to 500 and 1 to2000, and preferably about 1 to 1000.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a longitudinal viewthrough an anti-skid element according to the present invention, thesame being shown in a tire carcass.

FIGURE 2 is a transverse sectional view taken on line 22 of FIGURE 1.

FIGURE 3 is a transverse sectional view taken on line 3-3 of FIGURE 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,the same show an antiskid element according to the present invention,the same comprising a pin 1 which is slightly conical and which is madeof a hard, wear-resistant metal. The pin 1 is pressfit into a sleeve 2made of a light metal and projects from the lower end of the sleeve 2.As shown in FIGURE 1, the pin 1 is shorter than the blind bore 3 of thesleeve 2 and can, if necessary, press itself further into the bore 3.

The opposite end of the sleeve 2, i.e., the end which is located withinthe rubber tire 7, is in the form of an enlarged head 4, and both thehead 4 and the entire length of the shaft portion 5 of the sleeve 2 aresurrounded by a sheath 6, the entire anti-skid element incorporating thepin,.sleeve and sheath being anchored in the tire 7.

According to the present invention, the sheath 6 is made of a materialthat has two significant characteristics: it is elastic and it is a poorconductor of heat, as compared to the material of which the sleeve ismade, the latter being, for example, aluminum, copper, silver, or analloy of any of these metals. In practice, the sheath is made of asuitable polmer, such as polyethylene, polyvinyl chloride, a polyamidesuch as Perlon or nylon, polystyrene, polycarbonate, polypropylene, anacrylic resin such as Plexiglas, Orlon or Pan, polyisobutylene,polyvinyl ether, or polytetrafluoroethylene. These plastics have beenfound to possess the ability to prevent excessive heat from flowing fromthe antiskid element to the rubber mass within which the element isembedded, while at the same time these plastics are sufficiently elasticto prevent the entry of foreign particles between the sheath and theinner wall of the opening in the rubber within which the element islocated. In this way, the reasons for which heretofore known antiskidelements became loose are no longer present, so that the anti-skidelements according to the present invention will remain safely embeddedin the tire, even at high speeds. This not only prevents the loss oftraction, but also makes for a smoother and more quiet ride.

Thanks to the fact that the blind bore 3 of the sleeve 2 is at least aslong as the pin 1, the press-fit can continue to be reinforced, whichalso contributes to the quiet running of a tire equipped with anti-skidelements according to the present invention, as well as to increasedmileage which can be obtained from the tire.

Expressed in terms of measurable physical characteristics, the materialof which the sleeve is made will have a heat conductivity of betweenapproximately 100 and 400 kca'L/m. h. C., while the heat conductivity ofthe material of which the sheath is made will be much lower, namely,approximately 0.1 to 0.4 kcaL/m. h. C. In practice, the ratio of theheat conductivity of the material of which the sheath is made to theheat conductivity of the material of which the sleeve is made will bebetween 1 to 500 and 1 to 2000, the preferred ratio being of the orderof approximately 1 to 1000.

The following Table 1 sets forth several exemplary anti-skid elementsaccording to the present invention and gives the heat conductivities ofthe materials of which the sleeve and sheath are made, as well as theresulting ratio of heat conductivities.

TABLE 1 Sleeve material Sheath material Anti-skid and and Heatconelement heat conductivity heat conductivit ductivity No. (kcaL/m. h.C.) (kcaL/m. h. C.) ratio 1 Copper, 343 Polyethylene, 0. 32--.. 1-1, 0722 do Polyamide, 0.23 1-1,491 3 do Polyisobutylene, 0.30- 1-1, 143 4Silver, 350 lolyethyleue, 0. 32-.-- 1l, 093 5 Aluminum, 200.--..."Polyiginyl chloride, 1-1, 665

' 0. 6 ..do Polystyrene. 0.13 1,1-539 7 --do Polyvinyl ether, 0.11 1 11-1, 820 8 Alloy of 80% alumi- Polypropylene, 0.14..- 1-1, 000

num, 20% silicon, 140.

do Polycarbonate, 0.15... 1-933 Polyamide, 0. 23 1-609 Bronze (97%copper Polytetrafiuoroethyl- 1-722 n), 101. ene, 0. 14.

12 do Acrylic resin, 0. 16... 1-631 13 Brass (90% copper, Polyvinylchloride, 1-1, 290

Zinc), 155. 0.12. do... Polyvinyl ether, 0.11 l l l-l, 410 doPolypropylene, 0. 14... 1-1, 108

1 Estimated.

TABLE 2 [Dimensions in millimeters] Anti-skid element No.

a b c d e i g h i It will be understood that the above description ofthe present invention is susceptible to various modifications, changes,and adaptions, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

We claim:

1. An anti-skid element for tires, comprising, in combination:

(a) a pin made of wear-resistant material having a slight taper;

(b) a sleeve made of a material which is a good conductor of heat andhaving a blind bore which is longer than said pin and said pin beingpress-fit into said blind bore and projecting from one end thereof, theother end of said sleeve having an enlarged head; and

(c) a sheath surrounding said sleeve including said head thereof andbeing made of an elastic material which is a poor conductor of heat.

2. An anti-skid element as defined in claim 1 wherein said sheath ismade of a polymer.

3. An anti-skid element as defined in claim 2 wherein said polymer is apolyethylene, polyvinyl chloride, polyamide, polystyrene, polycarbonate,polypropylene, acrylic resin, polyisobutylene, polyvinyl ether, orpolytetrafluoroethylene.

4. An anti-skid element as defined in claim 2 wherein said sleeve ismade of aluminum, copper, silver, or an alby of any of the foregoing.

5. An anti-skid element as defined in claim 2 wherein the material ofwhich said sleeve is made has a heat conductivity of betweenapproximately and 400 kcal/ m. h. C.

6. An anti-skid element as defined in claim 2 wherein said polymer has aheat conductivity of between approximately 0.1 and 0.4 kcaL/m. h. C.

7. An anti-skid element as defined in claim 2 wherein the ratio of theheat conductivity of said polymer to the heat conductivity of thematerial of which said sleeve is made is between 1 to 500 and 1 to 2000.

8. An anti-skid element as defined in claim 7 wherein said ratio isapproximately 1 to 1000.

9. An anti-skid element as defined in claim 2 wherein said sheathextends throughout the entire length of said sleeve.

References Cited UNITED STATES PATENTS 2,982,325 5/1961 Pellaton 152-210FOREIGN PATENTS 1,419,090 1965 France.

ARTHUR L. LA POINT, Primary Examiner

